Drive system for fluid flow device

ABSTRACT

A drive system for a fluid flow device including a transmission member (e.g., a drive belt or the like) coupled to a drive motor and a fluid flow device such that the transmission member can be readily loosened without the use of extra tooling such as lifting jacks, sliding plates, or other lifting devices. In some embodiments, a drive belt may be removed from the fluid flow system by shifting the position of the drive motor relative to the fluid flow device through application of manual force from a user&#39;s hand. The drive system includes a drive motor mounted on a mounting platform that is pivotably coupled about a longitudinal axis to a base. At least a portion of the drive motor is disposed above the longitudinal axis of the mounting platform.

TECHNICAL FIELD

This invention relates to a drive system for a fluid flow device, andcertain embodiments related to coupling components for the drive system.

BACKGROUND

Fluid flow systems may be used in a variety of industrial applications,including fluid conveyance, chemical mixing and dispensing, materialdrying, material transport, product packaging, and others. These systemstypically include a fluid flow device, such as a vacuum pump, a rotaryblower, or the like. The fluid flow devices are powered by a drive motorthat is coupled to an input shaft of the fluid flow device. For example,a positive displacement rotary blower uses one or more impellers thatare rotatably mounted in a chamber formed in a casing. Fluid to beprocessed, such as air, is introduced into an inlet at one end of thecasing, and is forced by impellers to an outlet at the other end of thecasing. In general, at least one input shaft is coupled to the impellersto provide rotational power to the impellers. This rotational power istransmitted to the blower's input shaft from the motor's output shaft.In many instances, a drive belt couples the output shaft of the drivemotor to the input shaft of the blower.

Some fluid flow systems may include a rotary blower or vacuum pumpmounted on a common base with the drive motor. Certain packaged systemsmay have smaller motors in order to provide portable or temporary fluidcontrol solutions. Alternatively, the drive motor and fluid flow devicemay be mounted adjacent one another on a common base in more permanentapplications, such as waste water treatment plants. In either case,certain factors affect the design of fluid flow systems that use a drivemotor to transmit power to a fluid flow device.

The time and costs associated with system maintenance and repair is onefactor that affects the design of a fluid flow system. For example, thedrive belt that couples the drive motor to the rotary blower may needrepair or replacement during the life of the fluid flow system. In somecases, the drive belt can only be removed when the drive motor androtary blower are shifted closer to one another, which relieves thetension in the drive belt. A significant amount of labor and time may berequired to disconnect the drive motor from the base to shift theposition of the drive motor. In certain systems that have sizeable drivemotors (e.g., some 30-hp electric motors can weigh approximately 450 lbsor more), jacking equipment, sliding tracks, or other specializedlifting devices are required to shift the position of the drive motorand loosen the tension of the drive belt. This tooling can increase thecosts associated with the maintenance and repair of the fluid flowsystem. Moreover, additional time and tooling may be required toproperly tension the new drive belt after the drive motor and fluidcontrol device have been shifted back into the original positions.

Another factor that affects the design of the drive system of the fluidflow device is safety. In some circumstances, the drive motor and fluidflow device are spaced apart to increase the tension in the drive belt.If the drive belt is placed under sufficient stress, the belt may breakor become severely deformed. Depending on the construction of thesystem, the drive motor or the fluid flow device may unexpectedly shiftpositions when the tension in the belt is eliminated. Such unexpectedmovements may injure nearby workers or otherwise damage equipment.

SUMMARY

Certain embodiments of a fluid flow system provide a transmission member(e.g., a drive belt or the like) coupled to a drive motor and a fluidflow device such that the transmission member can be readily loosenedwithout the use of extra tooling such as lifting jacks, sliding plates,or other lifting devices. In some embodiments, a drive belt may beremoved from the fluid flow system by shifting the position of the drivemotor relative to the fluid flow device through application of manualforce from a user's hand.

In one illustrative embodiment, a system includes a drive motor that ispivotably coupled to a base about a first axis. The drive motor has anoutput member that is rotatable about a second axis. The second axis issubstantially parallel to and spaced apart from the first axis, and atleast a portion of the drive motor and the first axis are disposedvertically relative to one another. The system also includes a fluidflow device coupled to the base. The fluid flow device has an inputmember. The system further includes a transmission member to engage withthe output member and the input member to transmit rotational power fromthe drive motor to the fluid flow device.

This and other embodiments may be configured to provide one or more ofthe following advantages. First, the fluid flow system may include atransmission member (e.g., a drive belt or the like) that can be safelyloosened by applying a force from the user's hand to the side of thedrive motor or another component. Second, replacement of thetransmission member may be accomplished without the use of a liftingjack or other such devices. Third, the fluid flow system may include aself-tensioning apparatus to properly tension the transmission memberafter installation. Fourth, the system may include one or more safetymechanisms to limit the pivoting movement of the drive motor relative tothe base. Such safety mechanisms may prevent harm to the user or otherequipment in the event of transmission member breakage. Some or all ofthese and other advantages may be provided by the stretching systemsdescribed herein.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a front view of a fluid flow system in accordance with certainembodiments of the invention.

FIG. 2 is a right side view of the fluid flow system of FIG. 1.

FIG. 3 is a left side view of the fluid flow system of FIG. 1.

FIG. 4 is a top view of the fluid flow system of FIG. 1.

FIG. 5 is a front view of a fluid flow system with a drive motor in afirst position in accordance with certain embodiments of the invention.

FIG. 6 is a front view of the fluid flow system with a drive motor in asecond position in accordance with some embodiments of the invention.

FIG. 7 is a front view of a fluid flow system illustrating a portion ofan enclosure with a front panel removed.

FIG. 8 is a front view of the enclosure of the fluid flow system of FIG.7 with the front panel installed.

FIG. 9 is a top view of the enclosure of the fluid flow system of FIG.7.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

A number of embodiments of a fluid flow system provide a transmissionmember, such as a belt or cable, coupled to a drive motor and to a fluidflow device in a manner that permits the transmission member to bereadily loosened by application of manual force from a user's hand to acomponent of the system. In certain preferred embodiments, the drivebelt may be removed from the drive motor and/or the fluid flow devicewithout the use of extra tooling such as lifting jacks or other suchdevices.

Referring to FIGS. 1-4, a fluid flow system 100 includes a drive motor130 movably coupled to a base 110. In this embodiment, a mountingplatform 112 is rotatably engaged with the base portion 110 about alongitudinal axis 115. The motor 130 may be mounted to the platform 112such that the motor 130 is pivotably coupled to the base 110 and movableabout a longitudinal axis 115 of the platform 112. A fluid flow device150 is mounted to the base 110 and disposed laterally adjacent to thedrive motor 130. A transmission member 170, such as a belt, cable, orchain, is engaged with the drive motor 130 and the fluid flow device 150such that rotational power is transmitted from the drive motor 130 tothe fluid flow device 150.

Referring more closely to FIGS. 1-2, the fluid flow device 150 may havea casing 155 that at least partially surrounds an internal chamber. Aninput portion 152 of the fluid flow device 150 engages the transmissionmember 170. The input portion 152 may include an input shaft 154 and oneor more pulleys, gears, collars, or other devices to engage thetransmission member 170. The input shaft 154 rotates about an input axis156 and may cause one or more impellers (not shown in FIGS. 1-2) torotate in the internal chamber of the flow device 150, thereby forcingfluid to flow through the system 100. In this embodiment, the fluid flowdevice 150 is depicted as a positive displacement rotary blower havingmultiple impellers that deliver a large quantity of fluid relative tothe individual pulses. It should be understood that other fluid flowdevices, such as vacuum pumps, centrifugal flow control units, or otherrotationally powered flow devices, may be mounted to the base 110 andused in the fluid flow system 100.

An inlet filter 180 may be connected to the fluid flow device 150 toprevent undesirable matter from entering the fluid flow device 150. Theinlet filter 180 may be connected to the flow device 150 using a slip-onconnection, a threaded engagement, or other fastening devices. The inletfilter 180 is adapted to receive fluid from a source, such as a supplytank or from ambient air. The fluid flow system 100 may control the flowof almost any type of fluid, such as air, other gases, water, oil, otherliquids, or mixtures thereof. When the fluid flow system 100 isoperating, the fluid may be passed through the inlet filter 180 and intothe internal chamber of the fluid flow device 150.

Still referring to FIGS. 1-2, after the fluid is passed through theinternal chamber, the flow device 150 may force the fluid into adischarge silencer 185. The fluid flow device 150 may have pulsationwithin the piping system and in the vicinity of the flow device cancreate significant noise depending on the size and operational speed ofthe flow device. The discharge silencer 185 can be used to reduce thenoise levels emitting from the fluid flow system 100. The proper sizeand type of discharge silencer 185 may depend upon the fluid flow volumeand type of discharge fluid. The discharge silencer 185 may beintegrally manufactured with the base 110 or may be mounted to the base110 using specially sized mounting flanges. In addition or in thealternative, the discharge silencer 185 may be mounted to the flowdevice 150 using clamps, a threaded connection, a slip-on connection, awelded connection, or the like.

Referring to FIG. 2, the fluid may pass through the discharge silencer185 and out an exhaust port 188 (also shown in FIG. 4). Depending uponthe application in which the fluid flow system 100 is used, the variousstructures, such as a hose, tube, pipe, or the like, may be connected tothe exhaust port 188. The exhaust port 188 may include threads 189 orother engagement devices to which an output structure can be secured.

The fluid flow system 100 may include a pressure relief valve 190, asshown in FIG. 2 (refer also to FIG. 4). In the event that fluid isprevented from exiting through the exhaust port 188, the fluid mayescape the system 100 through the pressure relief valve 190.

Referring now to FIGS. 1 and 3, the drive motor 130 includes an outputportion 132 that supplies rotational power for operation of the fluidflow system 100. The output portion 132 may include a drive shaft 134and one or more pulleys, gears, collars, or other devices to engage thetransmission member 170. Thus, as the output portion 132 and drive shaft134 rotate about an output axis 136, the transmission member 170 causesthe input portion 152 to rotate about the input axis 156, therebysupplying power for the operation of the fluid flow device 150.

In this embodiment, the drive motor 130 is depicted as an electric motorhaving a NEMA frame. (The National Electrical Manufacturers Association(NEMA) has established industry-standard, base-mounted motordimensions.) The drive motor 130 depicted in this embodiment has asubstantially cylindrical casing 137 with fins 138 extending therefrom.Also, this embodiment of the drive motor 130 includes a junction box 139for electrical interconnection with a power source. It should beunderstood that other drive motors, such as gasoline-powered motors,electrical servo motors, or other rotational output devices, may bepivotably coupled to the base 110 and used in the fluid flow system 100.

Still referring to FIGS. 1 and 3, the drive motor 130 includes mountingflanges 135 that are connected to one or more mounting platforms 112(also shown in FIG. 4). In this embodiment, the platforms 112 aremounted to a shaft 114, which is rotatably engaged with the base 110.The shaft 114 is connected to the base 110 via a bearing connection 116such that the shaft is rotatable about the axis 115. Thus the drivemotor 130 is pivotably coupled with the base 110 such that the drivemotor 130 can pivot about the longitudinal axis 115 of platform 112relative to the base 110.

In one presently preferred embodiment, two platforms 112 are mounted tothe shaft 114 such that the one platform 112 may be adjusted relative tothe other platform 112 along the longitudinal axis 115. For example, abushing-and-setscrew connection may be used between each platform 112and the shaft 114 so that each platform 122 may be shifted along theshaft 114 and then locked into a desired position. As such, theplatforms 112 may be adjustable relative to one another to accommodatedriver motors 130 of various sizes. Furthermore, some embodiments mayinclude mounting platforms 112 having laterally extending slots throughwhich the motor's flanges 135 may be secured to the mounting platform bymeans of fasteners. These slots permit the drive motor 130 to belaterally shifted relative to the longitudinal axis 115. In theseembodiments, adjusting the lateral position of the drive motor 130 onthe mounting platforms 112 may accommodate driver motors 130 ortransmission members 170 of various sizes.

In this embodiment, the output axis 136 of the drive motor 130, theinput axis 156 of the flow device 150, and the longitudinal axis 115 ofthe platform 112 each extend in a substantially horizontal direction andare substantially parallel to one another. Accordingly, as the drivemotor 130 pivots about the longitudinal axis 115 of the platform 112,the output axis 136 and the input axis 156 remain substantially parallelto one another, yet the distance between the output axis 136 and theinput axis 156 is modified. For example, if the drive motor 130 ispivoted about the axis 115 toward the fluid flow device 150, thedistance between the output axis 136 and the input axis 156 isdecreased, thereby reducing the tension of the transmission member 170.On the other hand, if the drive motor 130 is pivoted about the axis 115away from the fluid flow device 150, the distance between the outputaxis 136 and the input axis 156 is increased, thereby increasing thetension of the transmission member 170.

In a preferred embodiment, the axis 115 and at least a portion of thedrive motor 130 are disposed vertically relative to one another (e.g.,at least a portion of the drive motor 130 is disposed above or below thelongitudinal axis 115 of the platform 112, as shown, for example, inFIG. 1). In such embodiments, moving the drive motor 130 to pivot aboutthe longitudinal axis 115 requires relatively lower amounts of force.Because a portion of the drive motor 130 is on each side of thelongitudinal axis 115, a user attempting to move the drive motor 130 isnot required to lift the entire weight of the drive motor 130. Rather,the user may apply a force with his or her hand to the side of the drivemotor 130 (or another component such as the platform 112) to create amoment about the axis 115, which causes the drive motor 130 to pivotabout the axis 115. If, on the other hand, the drive motor 130 waspositioned wholly outside of vertical relation with the axis 115 (e.g.,no portion of the drive motor 130 was disposed vertically above or belowthe axis 115), the amount of force required to pivot the drive motor 130about the axis 115 would be significant and, in some cases, would likelyrequire the use of a lifting jack.

In the embodiment shown in FIG. 1, the output axis 136 of the drivemotor 130 is positioned substantially vertically above the longitudinalaxis 115 so that at least one mounting flange 135 is disposed on eachside of the longitudinal axis 115 of the platform 112. In thisembodiment, a vertical plane through the longitudinal axis 115 and thecenter of mass of the drive motor 130 are spaced apart at a distance ofless than half the width of the drive motor 130. In some instances, thecenter of mass of the drive motor 130 may fall within the vertical planethrough the axis 115. As such, a user may move the drive motor 130 topivot about the longitudinal axis 115 with a reduced amount of force.

Referring now to FIGS. 1, 3, and 4, the fluid flow system 100 mayinclude a tensioning system 140 to maintain sufficient tension in thetransmission member 170. The tensioning system 140 includes a biasingmember, such as a spring 144, that urges the drive motor 130 to pivotabout the longitudinal axis 115 away from the flow device 150 so thatthe tension in the transmission member 170 is maintained. In thisembodiment, the tension system 140 includes a spring 144 that isdisposed around a threaded shaft 142. The spring 144 may be undercompression between a cap 143 and the platform 112 such that a downwardforce is applied to the platform 112. This compression force from thespring 144 creates a moment about the longitudinal axis which may beoffset by the tension in the transmission member 170. Thus, the forcefrom the spring 144 urges the drive motor 130 to pivot away from theflow device 150 while the tension in the transmission member 170 urgesthe drive motor 130 to pivot toward the flow device 150. Accordingly,the force from the spring can be adjusted to modify the static tensionin the transmission member 170 and maintain a proper tension in thetransmission member 170 while the drive motor 130 is operating.

In this embodiment, the force from the spring 144 can be modified byadjusting the position of the cap 143 along the threaded shaft 142. Forexample, the cap 143 (or nut disposed above the cap) can be screwedalong the threaded shaft 142 to adjust the position of the cap 143,thereby adjusting the compression of the spring 144. (The threads mayextend only along certain portions of the threaded shaft 142.) Thethreaded shaft 142 may be pivotably engaged with the base 110 so thatthe compression force from the spring 144 remains substantiallyperpendicular to the mounting platform 112. If, for example, themounting platform 112 is pivoted at a certain angle relative to the base110, the threaded shaft 142 may pivot to extend in a positionsubstantially normal to the platform 112. In the embodiment shown inFIG. 1, the threaded shaft 142 is attached to a mounting axle 146 thatis rotatably engaged with an angle bracket 147. Such an embodimentpermits the threaded shaft to pivot relative to the base 110.

The tensioning system 140 can maintain sufficient tension in thetransmission member 170 even if the transmission member 170 deformsduring operation of the fluid flow system 100. In some embodiments, thetransmission member 170 may comprise a material that is susceptible tocreep or other deformation, such as when the transmission member 170 isa belt or a cable comprising a polymer material. After a large number ofcycles during the operation of the drive motor 130, the tension in thebelt may cause the belt material to creep or otherwise deform such thatthe circumferential length of the belt is slightly increased. Thisdeformation or creep may reduce the tension in the belt if the distancebetween the output axis 136 and the input axis 156 remains unchanged. Areduction in tension may cause slippage or other inefficiencies betweenthe transmission member 170 and at least one of the output portion 132and the input portion 152. The tensioning system 140 may compensate forany gradual deformation of the transmission member 170 that occurs afternumerous cycles of the drive motor operation. In the event that thetransmission member 170 slightly deforms and increases incircumferential length (which may cause a reduction in the tensionforce), compression force from the spring 144 may cause the drive motor130 to slightly pivot away from the flow device 150. Thisself-tensioning adjustment by the tensioning system 140 shifts thedistance between the output axis 136 and the input axis 156 when areduction in the tension of member 170 occurs, thereby maintaining asufficient tension in the transmission member 170 during the operationof the fluid flow system 100.

Referring to FIG. 5, the fluid flow system 100 may include a safetymechanism 195 to reduce the likelihood of injuring a user or damagingequipment. In this embodiment, the safety mechanism 195 includes one ormore stoppers 196 and 197 to limit the rotation of the drive motor 130about the axis 115. As previously described, the drive motor 130 ispivotably coupled to the base 110 about the axis 115, and thecompression force from the spring 144 and the tension force in thetransmission member 170 cooperate to retain the drive motor 130 in anoperational position. In the event that the transmission member 170 isremoved, broken, or severely deforms, the drive motor 130 may pivot awayfrom the flow device 150. Such movement of the drive motor 130, ifunexpected, may cause injury to a nearby worker or damage to otherequipment.

As shown in FIG. 5, the stopper 196 may comprise a nut engaged with thethreaded shaft 142 so that the position of the stopper 196 isadjustable. The stopper 196 is adapted to intercept the mountingplatform 112 in order to limit the drive motor's pivoting movement.Thus, the higher the stopper 196 is positioned on the threaded shaft142, the greater the pivoting limitation is imposed on the drive motor130. In one example, if the transmission member 170 snaps at a breakagepoint 172, the drive motor 130 may be urged to pivot away from the flowdevice 150 (due to the force from the spring 144, the position of themotor's center of mass relative to the longitudinal axis 115, or both).If the drive motor 130 is permitted to freely pivot in that direction,the platforms 112 or a part of the drive motor 130 (e.g., the electricaljunction box 139) may unexpectedly strike a nearby worker or some pieceof equipment. In this embodiment, the stopper 196 limits the degree ofdrive motor's pivoting movement to reduce the likelihood of suchinjuries or damage. In certain embodiments, the safety mechanism 195 maylimit the drive motor's pivoting movement to no more than 20° from thevertical. In some presently preferred embodiments, the safety mechanism195 limits the drive motor's pivoting movement to about 5° or less fromthe vertical.

Still referring to FIG. 5, the safety mechanism 195 may also include asecond stopper 197 on the opposite side of the drive motor 130 from thefirst stopper 196. In this embodiment, the second stopper 197 isdepicted as an angle bracket that is attached to the base 110. Thesecond stopper 197 is disposed proximal to the mounting platform 112 soas to intercept the mounting platform 112 at a certain position, therebylimiting the drive motor's pivoting movement in the direction toward theflow device 150. The first and second stoppers 196 and 197 of the safetymechanism 195 are not limited to the threaded nut or the angle bracketshown in FIG. 5. Rather, each stopper 196 or 197 may comprise anactuator, flange, rod, cable, or other device to limit the pivotingmovement of the drive motor 130 at certain positions.

Referring now to FIG. 6, the fluid flow system 100 may be operated suchthat the transmission member 170 can be readily replaced and thenproperly tensioned. In some embodiments, the transmission member 170 canbe sufficiently loosened by application of manual force from a user'shand 104 without the use of lifting devices such as lifting jacks orsliding plates. For example, a drive belt may be removed from the fluidflow system 100 by shifting the position of the drive motor 130 relativeto the fluid flow device 150 without the use of extra tooling such aslifting jacks, sliding plates, or other lifting devices. The drive motor130 can be pivoted about the longitudinal axis 115 through applicationof a force 102 from the user 104 against the side of the drive motor 130or another component.

As shown in FIG. 6, when the transmission member 170 is in need ofreplacement, a user may apply a force 102 to some portion of the drivemotor 130 (or another component such as the platform 112) to create amoment about the axis 115, which causes the drive motor 130 to pivottoward the fluid flow device 150. In some circumstances, the user maychoose to raise the position of the cap 143 to relieve the compressionof the spring 144. By relieving the compression of the spring 144, theforce 102 required to pivot the drive motor 130 toward the flow device150 may be reduced. In this embodiment, the force 102 required to shiftthe position of the drive motor 130 may be applied directly from theuser's hand 104 or from an instrument held in the user's hand 104. Asshown in FIG. 6, the user may shift the position of the drive motor 130to the maximum rotation permitted by the second stopper 197 in order toprepare the transmission member 170 for removal. It should be understoodthat, in some embodiments, the transmission member 170 may besufficiently loosened for removal without forcing the drive motor 130 topivot to the maximum rotation permitted by the stopper 197.

Still referring to FIG. 6, when the force 102 is applied to pivot thedrive motor 130 about the longitudinal axis 115 toward the fluid flowdevice 150, the distance 105 between the output axis 136 and the inputaxis 156 is decreased. As previously described, the tension of thetransmission member 170 is reduced when the distance between the outputaxis 136 and the input axis 156 is decreased. At a point when thetension in the transmission member 170 is sufficiently reduced, the usermay grasp the transmission member 170 with a hand 106 (or a handheldinstrument) and pull the transmission member away from either the outputportion 132 or the input portion 152.

After the transmission member 170 is removed from the fluid system 100,a replacement transmission member 170 can be installed. With the drivemotor 130 pivoted toward the fluid flow device 150 (refer, for example,to FIG. 6), the user may engage the replacement transmission member 170with the output portion 132 of the drive motor 130 and the input portion152 of the flow device 150. Then the user may release the force 102 andpermit the drive motor 130 to pivot to a steady-state position (whilethe replacement transmission member is engaged with both the outputportion 132 and the input portion 152). The user may adjust the positionof the cap 143 along the threaded shaft 142 to increase or decrease thecompression of the spring 144 so that the transmission member 170 is setto a proper tension. Optionally, a force transducer or another measuringdevice may be connected to the transmission member 170 to measure thetension. As previously described, even after the drive motor 130 hasoperated through numerous cycles, the tensioning system 140 can maintainsufficient tension in the transmission member 170 and compensate forminor changes in the transmission member's circumferential length.

Accordingly, certain embodiments of the fluid flow system 100 include atransmission member 170 that can be safely loosened and removed withoutthe use of a lifting jack or other such devices. Furthermore, suchreplacement of the transmission member 170 may be accomplished byapplying a force from the user's hand or handheld instruments. Thesefeatures may reduce the labor and costs associated with the maintenanceof the transmission member 170 in fluid flow systems.

Referring to FIGS. 7-9, some embodiments of the fluid flow system 100may be mounted in an enclosure 200. In this embodiment, the enclosure200 includes a front panel 210 (FIG. 8), two side panels 220 and 230, arear panel 240, a top panel 250, and an enclosure base 260. The sidepanels 220 and 230 include vents 222 and 232 to permit airflow in andout of the enclosure 200. The enclosure base 260 includes asubstantially planar portion 262 onto which the fluid flow system 100 ismounted. One or more mounting flanges 264 may be attached to theenclosure base 260 so that the enclosure 200 may be secured to theground or another surface. The enclosure 200 may also include a pressuremeasurement system 270 that displays pressure measurement information.For example, the pressure measurement system 270 may include a firstgauge 272 to display the pressure measurement in the inlet filet 180 anda second gauge 274 to display the pressure measurement at the exhaustport 188.

As shown in FIGS. 7 and 8, the front panel 210 may be removable from theenclosure 200 to provide access to the fluid flow system 100 mountedtherein. Thus, a user may perform maintenance on the transmission member170 or other components of the fluid flow system 100 without removingthe system 100 from the enclosure 200. In this embodiment, the frontpanel 210 may be partially removed to reveal a safety screen 212 (FIG.8). As such, a user may remove a portion of the front panel 210 and viewinto the enclosure 200 without exposing any limbs or instruments to themoving components of the fluid flow system 100 mounted therein. In suchembodiments, the front panel 210 (including the safety screen 212) maybe wholly removed from the enclosure 200 to provide access inside theenclosure 200, or the front panel 210 may be partially removed such thatthe safety screen 212 remains connected to the enclosure 200.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other embodiments are within the scope of the followingclaims.

1. A drive system for a fluid flow device, comprising: a drive motorpivotably coupled to a base about a first longitudinal axis, the drivemotor having an output member that is rotatable about a second axis thatis substantially parallel to and spaced apart from the first axis,wherein at least a portion of the drive motor is disposed verticallyabove or below the first longitudinal axis; a fluid flow device coupledto the base, the fluid flow device having an input member; and atransmission member to engage with the output member and the inputmember to transmit rotational power from the drive motor to the fluidflow device.
 2. The system of claim 1, wherein when the drive motor isin a first operative position relative to the base, the transmissionmember is under tension and engaged with output member and the inputmember.
 3. The system of claim 2, wherein when the drive motor is in asecond operative position relative to the base, tension in thetransmission member is reduced such that the transmission member isdisengagable from at least one of the output member or input member. 4.The system of claim 3, wherein the drive motor is pivoted about thefirst longitudinal axis toward the fluid flow device when in the secondoperative position.
 5. The system of claim 1, wherein the drive motor ispivotably coupled to the base about the first axis such that the drivemotor is pivotably movable from a first operative position to a secondoperative position by application of manual force from a user.
 6. Thesystem of claim 1, wherein the transmission member is disengagable fromat least one of the output member or input member by application ofmanual force from a user to pivot the drive motor about the firstlongitudinal axis.
 7. The system of claim 1, wherein the drive motorweighs at least 85 lbs and is pivotably coupled about the firstlongitudinal axis such that the drive motor is movable relative to thefluid flow device by application of manual force from a user's handwithout aid from a separate lifting device.
 8. The system of claim 1,further comprising a safety mechanism to limit the drive motor'spivoting movement about the first axis, wherein the safety mechanismincludes at least one stopper that prevents the drive motor frompivoting more than 20 degrees from vertical.
 9. The system of claim 1,further comprising a self-tensioning apparatus to apply a bias force toa component of the system such that a moment is created about the firstlongitudinal axis to urge the drive motor to pivot away from the fluidflow device.
 10. The system of claim 1, further comprising a firstmounting platform pivotably coupled to the base about the longitudinalaxis, wherein the drive motor is mounted to the first mounting platform.11. The system of claim 11, further comprising a second mountingplatform pivotably coupled to the base about the longitudinal axis, thesecond mounting platform being adjustable along the longitudinal axisrelative to the first mounting platform, wherein the drive motor ismounted on the first and second mounting platforms.
 12. The system ofclaim 1, wherein the drive motor is an electric NEMA frame motor. 13.The system of claim 1, wherein the fluid flow device is selected fromthe group consisting of rotary blowers, vacuum pumps, and centrifugalflow control units.
 14. The system of claim 1, wherein the transmissionmember is selected from a group consisting of belts, chains, and cables.15. A drive system for a fluid flow device comprising: a drive motordisposed on a mounting platform, said mounting platform pivotablycoupled about a longitudinal axis to a base, said drive motor having anoutput member that is rotatable about a second axis that issubstantially parallel to and spaced apart from the first longitudinalaxis, wherein at least a portion of the drive motor is disposedvertically above the first longitudinal axis of the mounting platform; afluid flow device coupled to the base, the fluid flow device having aninput member; and a transmission member to engage with the output memberof the drive motor and the input member of the fluid flow device totransmit rotational power from the drive motor to the fluid flow device.16. The drive system of claim 15, wherein the drive motor is positionedon the mounting platform such that a center of mass of the drive motoris disposed a distance of less than half the width of the drive motorapart from a vertical plane passing through the longitudinal axis of themounting platform.
 17. The drive system of claim 15, wherein a center ofmass of the drive motor is positioned substantially above thelongitudinal axis of the mounting platform.
 18. The drive system ofclaim 15, further comprising a second mounting platform pivotablycoupled about the longitudinal axis to the base, the second mountingplatform being adjustable along the longitudinal axis relative to thefirst mounting platform; wherein the drive motor is disposed on thefirst and second mounting platforms.
 19. A method for replacing a drivebelt for a drive system of a fluid flow device, said method comprising:reducing tension in a drive belt by pivoting a drive motor about a firstlongitudinal axis toward a fluid flow device, the first longitudinalaxis and at least a portion of the drive motor being disposed verticallyabove or below the longitudinal axis, wherein the drive motor has anoutput member that is rotatable about a second axis that issubstantially parallel to and spaced apart from the first axis, andwherein the drive belt is engaged with the output portion of the drivemotor and an input portion of the fluid flow device; and removing thedrive belt from at least one of the output portion of the drive motorand the input portion of the fluid flow device.
 20. The method of claim19, wherein reducing tension in the drive belt comprises applying manualforce from a user's hand to pivot the drive motor about the firstlongitudinal axis.
 21. The method of claim 20, wherein the drive motorweighs at least 85 lbs and is pivotably coupled about the first axissuch that the drive motor is movable relative to the fluid flow deviceby application of manual force from the user's hand without aid from alifting device.
 22. The method of claim 19, further comprising engaginga replacement drive belt with the output portion of the drive motor andthe input portion of the fluid flow device.
 23. The method of claim 22,further comprising increasing tension in the replacement drive belt bypivoting the drive motor about a first longitudinal axis away from thefluid flow device.
 24. The method of claim 23, further comprisingarranging a self-tensioning apparatus to apply a bias force such that amoment about the first longitudinal axis is created to urge the drivemotor to pivot about the first longitudinal axis away from the fluidflow device.